On (1): Different people have different reasons to be vegetarian. Besides the ones mentioned, there are many others. One important one, nowadays, is an environmental concern. Animal farms emit enormous amounts of greenhouse gases; they produce large amounts of pollution; etc. It's also true that animals raised for slaughter are fed a lot more protein (and other foodstuffs) than they will ever produce. They are, if one wants to think of them this way, very inefficient food factories. Regarding the latter part of (1), obviously this depends upon one's reasons, but most vegetarians I know would never carry an alligator bag. On (2), I'm not sure I understand the question, but perhaps the point is that shrimp, crabs, and insects do not plausibly suffer. If that is the point, I don't disagree, actually. If one's reason not to eat chicken, say, is that chickens are intelligent, sentient creatures, etc, etc, then this reason certainly does not apply to scallops, or shrimp, so far as I can see. There will...

This is an interesting question. It's related, in a way, to a famous objection to Descartes's "I think, therefore I am". The objection was: What's with the I? Why not just: Some thinking is happening? So maybe the dog can be thinking: Petting would be good. Eating is good. Baths are bad! Frisbee is good! Etc, etc. Another important point to make is that one doesn't have to think that dogs have the same worth or dignity as human beings to think they have worth and dignity, even that they have quite a lot of worth and dignity. Personally, I'm more of a cat person, and, whether or not my cats are self-conscious, they are sophisticated social beings, with each of whom I have a complex, individual, and mutual relationship. There are no doubt limits to their mental capacities. But there are limits to our mental capacities, too. And I think it would definitely go too far to say that they have no appreciation at all of the difference between minded and unminded things. There are lots of things they do...

But I think you have what philosophers call the "dialectic" of the argument here somewhat backwards. I take it that the argument for vegetarianism is suppose to be something like this: (i) The lives of animals are of moral significance, which is to say that one cannot permissibly kill an animal without good reason; (ii) The need to eat would constitute good reason, but (iii) as a matter of empirical fact, most of us, at least in developed countries, do not need to kill animals to eat, so we do not have such reason; (iv) Mere preference for animal flesh over plant-based foods does not amount to sufficient reason to kill an animal; (v) So we fortunate people living in developed countries ought not to kill animals for food. So the argument is not really that we do not need to eat animals to survive. It should be clear that the argument does indeed grant that, if one has to kill other animals in order to survive, then that would be morally permissible. But even so, this does not mean that killing those...

Sorry, but this is a silly argument. Replace "animal" with "person", and you get an argument in favor of breeding children for slaughter. ( Apologies to Jonathan Swift .) But yet, surely, it's better for a person to exist than for it not to exist, right? Actually, that's not so obvious, as we'll shortly see. But if it's not obvious in the case of people, it's certainly not obvious in the case of animals. The argument purports to show that it's (objectively) better for an animal to exist than for it not to exist by showing that, if it were (objectively) better for it not to exist, then we ought to sterilize all the cows. But this assumes that, if it's not (objectively) better for an animal to exist than for it not to exist, then it must be (objectively) better for it not to exist. But the obvious reply is that there's just no better or worse about it. It's neither (objectively) better for one more cow to exist nor (objectively) worse. But then the argument goes nowhere. What's fundamentally...

Sure, it's possible. And here's how it could be established. Suppose it were found that, when and only when people dream, certain things happen in their brains. And suppose that dogs' brains are similar in relevant respects to people's brains and that, lo and behold, their brains exhibit similar behavior when they sleep. That, it seems to me, is excellent reason to suppose that dogs dream. It's not "proof", but, as has often been said here, we don't have "proof" of very much: I don't have any proof that you dream, or even that you exist, but I nonetheless know that you do.

It is crucial, I think, to recognize that the relevant question here is not: Are the lives of humans more valuable than the lives of (other) animals? The objection to killing animals need not presuppose that animals' lives and humans' lives are of equal value. Most defenders of animal rights would not, I think, hold such a view. Their claim, rather, is that animals' lives are of sufficiently great value that they ought not to be killed. Note that saying that animals ought not to be killed does not imply that it is never morally permissible to kill an animal. Humans ought not to be killed, but most people would hold that it is sometimes morally permissible to kill human beings, for example, in self-defense. If (say) cows lives are of less value than are the lives of humans, then there may be circumstances in which it is permissible to kill a cow but in which it would not be permissible to kill a human being. But it does not follow from that fact that it is permissible to kill a cow just...

It seems to me that it is sufficient if there is a description of the act under which both parties consent to it. (I find myself tempted to say: ...and under which they both perform it. That may not be necessary but probably is.) Whether there are other descriptions under which one or another of the two parties has not consented to it seems irrelevant (especially if it is not a description under which they perform it): It will always be possible to find such descriptions. (Note that this is different from saying that there are descriptions under which one of the parties would withhold consent. Whether the existence of such descriptions would be relevant is a more difficult question.) If so, then the fact that X and Y, in the first example, happen to think of the consequences of their encounter in different terms does not seem to undermine their consenting to: having a sexual encounter. (And that, of course, is a description under which both of them perform the act.) There are undoubtedly...

A few points. First, I don't understand why you think one can't suffer without reflecting on the reasons for one's pain. That just seems false, and the OED seems to agree with me: suffer (v.) To have (something painful, distressing, or injurious) inflicted orimposed upon one; to submit to with pain, distress, or grief. Nor do I see why one cannot be tortured if one cannot reflect in this way. And again, the OED would seem to agree: torture (v.) 2. To inflict severe pain or suffering upon; to torment; to distress orafflict grievously; also, to exercise the mind severely, to puzzle orperplex greatly. Also absol. to cause extreme pain. That said, it's an interesting empirical question to what extent animals are capable of " reflect[ing] upon the reasons for or context of the pains they experience". So far as I know, however, the view you ascribe to "some researchers" is not a majority view.

Well, if that were the argument one had used, one would be in a bind. But I doubt many people are vegetarians for that reason. Nonetheless, most people, vegetarian or otherwise, think it wrong to cause animals unnecessary suffering. If it turned out that plants (say, grasses) feel pain, then I take it most people would be in a bind. Fortunately, there doesn't seem much prospect that organisms with no nervous system (let alone a central nervous system) feel pain.

Here's a more basic question: Do (non-human) animals know that they are ? Do (non-human) animals have a conception of themselves ? Are they, as it is put, "self-conscious"? Self-consciosuness seems to be a necessary precondition of knowledge of one's own mortality. Obviously, one need not give a single answer for all (non-human) animals. Perhaps birds are not self-conscious, but chimpanzees are. If one thought, as some philosophers have, that one cannot be self-conscious unless one is a user of language, then of course that would answer the question. But I don't find that view terribly appealing or well-argued. The question which animals are self-conscious is, presumably, an empirical one. I'm reasonably sure that flies are not self-conscious, but would be prepared to believe that cats are, and I've encountered some evidence that chimpanzees are. But there is a philosophical question here, as well, namely: What exactly is self-consciousness? What is involved in having a conception of...